What Is Roofing Felt?
When you’re getting a new roof or repairing an old one, you might hear your contractor talk about roofing felt—but what exactly is it?
If you’re asking, “What is roofing felt?”, you’re not alone. It’s one of the most common components in modern roofing systems, yet many homeowners don’t fully understand its role. In this guide, we’ll break it down in simple terms: what it is, what it does, and whether it’s still the best option for your roof today.
What Is Roofing Felt?
Roofing felt—also known as roof felt, felt paper, or roof underlayment—is a protective layer that sits between your roof deck (usually plywood or OSB) and the final roofing material, like shingles or tiles.
Traditionally made of felt paper soaked in asphalt, this material acts as a moisture barrier, shielding your roof deck from rain, wind-driven snow, and condensation before and after shingle installation.
What Is Felt Used For in Roofing?
Here’s what felt is used for in roofing:
- Moisture Protection: It adds a layer of water resistance.
- Backup Barrier: It protects the roof in case shingles are damaged or missing.
- Shingle Installation Base: It provides a clean, even surface for installing shingles.
- Fire Rating: Some felts improve the fire rating of roofing systems.
- Prevent Sap Leaching: Stops sap from certain wood decks from staining shingles.
In short, it’s a critical backup layer that increases the life and performance of your roof.
What Is Felt Paper for on Roofs?
Felt paper is the traditional form of roofing felt. It’s made from natural or synthetic materials soaked in bitumen or asphalt. This creates a strong, water-resistant sheet that’s rolled out over the roof deck.
When people ask, “What is felt paper for on roof?”, the answer is simple: it’s an underlayment designed to block water and protect your home if shingles blow off or become damaged.
What Is Felt Roof?
The term “felt roof” usually refers to a flat or low-slope roof that’s finished using layers of felt and bitumen. This system is common in garages, sheds, and commercial buildings. It’s applied in layers and sometimes torched down or bonded with adhesives.
Felt roofs are:
- Budget-friendly
- Easy to install
- Suitable for smaller or temporary structures
But they’re not always the best option for long-term protection—especially when there are better alternatives than roofing felt, which we’ll cover next.
What Is Better Than Roofing Felt?
While roofing felt is reliable and widely used, modern materials have taken its place in many high-performance roofing systems. If you’re wondering, “What is better than roofing felt?”, here are a few options:
- Synthetic Underlayment: Lighter, more durable, and often waterproof. Brands like GAF Deck-Armor or Owens Corning ProArmor lead the way.
- Peel-and-Stick Membranes: Self-adhering and waterproof, great for ice-prone areas.
- Rubberized Asphalt Membranes: Offer high water resistance and are used in premium roofing systems.
These modern materials outperform traditional felt in terms of durability, weight, UV resistance, and installation time.
Different Types of Roofing Felt
There are a few main types of roofing felt based on weight and material:
- 15 lb Felt – Lightweight and more affordable, used in basic roofing applications.
- 30 lb Felt – Thicker and more durable, better for steep-slope or high-wind areas.
- Synthetic Felt – A modern alternative to asphalt-based felt, made of woven polymers.
Each type serves different purposes, so your roofer will choose the right one based on climate, roof pitch, and roofing material.
Is Roofing Felt Always Necessary?
Yes, in most roofing systems, roofing felt or another type of underlayment is required by code and manufacturer warranties. It adds a vital layer of protection and increases roof lifespan.
However, in some regions or for temporary structures (like sheds), contractors may skip felt—but it’s not recommended for homes or permanent buildings.
Conclusion
So, what is roofing felt? It’s the unsung hero beneath your shingles—a water-resistant, protective barrier that guards your home from leaks, wind, and weather damage. Whether you call it roof felt, felt paper, or underlayment, it plays a vital role in the integrity of your roofing system.
Today, synthetic alternatives are often better than roofing felt, offering longer lifespan and improved performance. But traditional felt still has its place in many roofing projects.
If you’re re-roofing or installing a new roof and wondering what is felt used for in roofing, now you know—it’s a layer of security your home can’t afford to skip.
Need help figuring out what type of roofing felt is best for your Toledo home? Contact Pro Craft Home Products for expert guidance and a free roof inspection.
FAQs About Roofing Felt
Q: What is roofing felt made of?
A: Traditional roofing felt is made from paper or fiberglass saturated with asphalt. Synthetic felt is made of polypropylene or polyester.
Q: Can you roof without felt?
A: In most cases, no. Roofing felt or synthetic underlayment is required by building codes and warranties.
Q: How long does roofing felt last?
A: Asphalt-based felt can last 10–20 years, while synthetic underlayment can last up to 50 years depending on the brand and conditions.
Q: What is better than roofing felt?
A: Synthetic underlayment, peel-and-stick membranes, and rubberized asphalt sheets all offer superior performance.
